Currently, within integrated circuits there exist controllable capacitive devices produced in the form of micro electromechanical systems (MEMS). It is possible to cite in this regard the article by DeReus and others entitled “Tunable capacitor series/shunt design for integrated tunable wireless front end applications,” MEMS 2011, Cancun, Mexico, Jan. 23-27 2011, 2011 IEEE.
The capacitive device described in this article is based on a structure of the suspended bridge type comprising a metallic membrane disposed some distance from a lower electrode surmounted by a dielectric layer. When the membrane is distant from the dielectric layer, the capacitive device exhibits a first, typically low, capacitive value, while when the membrane is actuated so as to contact the dielectric layer, the metallic membrane/dielectric layer/lower electrode assembly forms a capacitor having a second, typically high, capacitive value.
The control of the flexing of the metallic membrane is performed by applying a high voltage, typically of the order of 50 volts, so as to ensure at one and the same time correct flexing of the mobile electrode and to ensure correct contact with the dielectric layer.
In addition to the fact that the technology used to produce such devices is a dedicated technology, which is difficult to integrate into a CMOS standard technological trend, the necessity to apply a high voltage, of the order of several tens of volts, is a major drawback.